1. Field of the Invention
The invention relates to a crystalline aluminosilicate zeolite-containing silica-alumina cracking catalyst and to a method of preparing same. More particularly, it relates to such catalyst that is made attrition resistant, more active, selective and stable by steps comprising forming a hydrogel, wet processing and homogenizing same, spray drying and rare earth impregnation.
2. Discussion of the Prior Art
Cracking catalysts are solid materials that have acidic properties. Because of the nature of the reactions taking place, the catalyst must have high porosity. Furthermore, since the catalyst circulates rapidly between reaction zones and burning, or regeneration zones, it must also have resistance to abrasion, temperature changes and the like.
Natural catalysts are composed principally of silica and alumina, but they contain certain other materials which may be harmful under certain circumstances. The synthetic silica-alumina materials are generally made from pure materials so that many of the shortcomings of the natural materials have been overcome. However, the catalysts made using silica-alumina prepared by prior art processes are subject to excessive attrition, aging and loss of activity and selectivity. The invention as described hereinafter has not been described or suggested in any prior art of which applicants are aware.